BACKGROUND: Two-dimensional and Doppler echocardiography are standard methods to assess the severity of pulmonic insufficiency (PI). However, methods to define severity of PI - including the current published guidelines - remain qualitative and unvalidated.METHODS: We reviewed all the electronic reports of echocardiographic studies performed at our institution since the publication of the 2003 American Society of Echocardiography guidelines on native valvular regurgitation. There were 8,279 instances of severe valvular insufficiency among 100,167 echocardiographic studies (approximately 90% transthoracic and 10% transesophageal). We also searched for uncommon findings of severe PI.RESULTS: Of all forms of severe valvular insufficiency, PI was least common. There were 135 instances of severe PI as defined by the existing guidelines; they accounted for only 1.6% of all instances of severe valvular insufficiency. Premature closure of the tricuspid valve was seen in 6.6%, holodiastolic flow reversal in 3.7%, premature opening of the pulmonic valve in 1.5%, PI with laminar retrograde flow in 1.5%, very low peak velocity of the PI jet in 1.5% of patients with severe PI.CONCLUSIONS: The published criteria do not include in detail the subtle signs of severe PI such as (1) holodiastolic flow reversal in the pulmonary artery, (2) PI with laminar retrograde flow, (3) premature opening of the pulmonic valve, (4) very low peak velocity of the PI jet, and (5) premature closure of the tricuspid valve. These signs should be considered in the grading of PI severity in addition to the existing guidelines criteria.